--- /dev/null
+/*
+ * jutils.c
+ *
+ * Copyright (C) 1991-1996, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains tables and miscellaneous utility routines needed
+ * for both compression and decompression.
+ * Note we prefix all global names with "j" to minimize conflicts with
+ * a surrounding application.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/*
+ * jpeg_zigzag_order[i] is the zigzag-order position of the i'th element
+ * of a DCT block read in natural order (left to right, top to bottom).
+ */
+
+#if 0 /* This table is not actually needed in v6a */
+
+const int jpeg_zigzag_order[DCTSIZE2] = {
+ 0, 1, 5, 6, 14, 15, 27, 28,
+ 2, 4, 7, 13, 16, 26, 29, 42,
+ 3, 8, 12, 17, 25, 30, 41, 43,
+ 9, 11, 18, 24, 31, 40, 44, 53,
+ 10, 19, 23, 32, 39, 45, 52, 54,
+ 20, 22, 33, 38, 46, 51, 55, 60,
+ 21, 34, 37, 47, 50, 56, 59, 61,
+ 35, 36, 48, 49, 57, 58, 62, 63
+};
+
+#endif
+
+/*
+ * jpeg_natural_order[i] is the natural-order position of the i'th element
+ * of zigzag order.
+ *
+ * When reading corrupted data, the Huffman decoders could attempt
+ * to reference an entry beyond the end of this array (if the decoded
+ * zero run length reaches past the end of the block). To prevent
+ * wild stores without adding an inner-loop test, we put some extra
+ * "63"s after the real entries. This will cause the extra coefficient
+ * to be stored in location 63 of the block, not somewhere random.
+ * The worst case would be a run-length of 15, which means we need 16
+ * fake entries.
+ */
+
+const int jpeg_natural_order[DCTSIZE2+16] = {
+ 0, 1, 8, 16, 9, 2, 3, 10,
+ 17, 24, 32, 25, 18, 11, 4, 5,
+ 12, 19, 26, 33, 40, 48, 41, 34,
+ 27, 20, 13, 6, 7, 14, 21, 28,
+ 35, 42, 49, 56, 57, 50, 43, 36,
+ 29, 22, 15, 23, 30, 37, 44, 51,
+ 58, 59, 52, 45, 38, 31, 39, 46,
+ 53, 60, 61, 54, 47, 55, 62, 63,
+ 63, 63, 63, 63, 63, 63, 63, 63, /* extra entries for safety in decoder */
+ 63, 63, 63, 63, 63, 63, 63, 63
+};
+
+
+/*
+ * Arithmetic utilities
+ */
+
+GLOBAL(long)
+jdiv_round_up (long a, long b)
+/* Compute a/b rounded up to next integer, ie, ceil(a/b) */
+/* Assumes a >= 0, b > 0 */
+{
+ return (a + b - 1L) / b;
+}
+
+
+GLOBAL(long)
+jround_up (long a, long b)
+/* Compute a rounded up to next multiple of b, ie, ceil(a/b)*b */
+/* Assumes a >= 0, b > 0 */
+{
+ a += b - 1L;
+ return a - (a % b);
+}
+
+
+/* On normal machines we can apply MEMCOPY() and MEMZERO() to sample arrays
+ * and coefficient-block arrays. This won't work on 80x86 because the arrays
+ * are FAR and we're assuming a small-pointer memory model. However, some
+ * DOS compilers provide far-pointer versions of memcpy() and memset() even
+ * in the small-model libraries. These will be used if USE_FMEM is defined.
+ * Otherwise, the routines below do it the hard way. (The performance cost
+ * is not all that great, because these routines aren't very heavily used.)
+ */
+
+#ifndef NEED_FAR_POINTERS /* normal case, same as regular macros */
+#define FMEMCOPY(dest,src,size) MEMCOPY(dest,src,size)
+#define FMEMZERO(target,size) MEMZERO(target,size)
+#else /* 80x86 case, define if we can */
+#ifdef USE_FMEM
+#define FMEMCOPY(dest,src,size) _fmemcpy((void FAR *)(dest), (const void FAR *)(src), (size_t)(size))
+#define FMEMZERO(target,size) _fmemset((void FAR *)(target), 0, (size_t)(size))
+#endif
+#endif
+
+
+GLOBAL(void)
+jcopy_sample_rows (JSAMPARRAY input_array, int source_row,
+ JSAMPARRAY output_array, int dest_row,
+ int num_rows, JDIMENSION num_cols)
+/* Copy some rows of samples from one place to another.
+ * num_rows rows are copied from input_array[source_row++]
+ * to output_array[dest_row++]; these areas may overlap for duplication.
+ * The source and destination arrays must be at least as wide as num_cols.
+ */
+{
+ register JSAMPROW inptr, outptr;
+#ifdef FMEMCOPY
+ register size_t count = (size_t) (num_cols * SIZEOF(JSAMPLE));
+#else
+ register JDIMENSION count;
+#endif
+ register int row;
+
+ input_array += source_row;
+ output_array += dest_row;
+
+ for (row = num_rows; row > 0; row--) {
+ inptr = *input_array++;
+ outptr = *output_array++;
+#ifdef FMEMCOPY
+ FMEMCOPY(outptr, inptr, count);
+#else
+ for (count = num_cols; count > 0; count--)
+ *outptr++ = *inptr++; /* needn't bother with GETJSAMPLE() here */
+#endif
+ }
+}
+
+
+GLOBAL(void)
+jcopy_block_row (JBLOCKROW input_row, JBLOCKROW output_row,
+ JDIMENSION num_blocks)
+/* Copy a row of coefficient blocks from one place to another. */
+{
+#ifdef FMEMCOPY
+ FMEMCOPY(output_row, input_row, num_blocks * (DCTSIZE2 * SIZEOF(JCOEF)));
+#else
+ register JCOEFPTR inptr, outptr;
+ register long count;
+
+ inptr = (JCOEFPTR) input_row;
+ outptr = (JCOEFPTR) output_row;
+ for (count = (long) num_blocks * DCTSIZE2; count > 0; count--) {
+ *outptr++ = *inptr++;
+ }
+#endif
+}
+
+
+GLOBAL(void)
+jzero_far (void FAR * target, size_t bytestozero)
+/* Zero out a chunk of FAR memory. */
+/* This might be sample-array data, block-array data, or alloc_large data. */
+{
+#ifdef FMEMZERO
+ FMEMZERO(target, bytestozero);
+#else
+ register char FAR * ptr = (char FAR *) target;
+ register size_t count;
+
+ for (count = bytestozero; count > 0; count--) {
+ *ptr++ = 0;
+ }
+#endif
+}
projects / opencv / blobdiff